1. Field of the Invention
The present invention relates generally to an apparatus for injecting resin for use in repairing composite structures and more particularly to an apparatus that is capable of injecting resin, which is maintained under uniform pressure conditions, into a composite structure at a controlled depth.
2. Description of the Prior Art
In composite structures, defects such as delaminations, cracks, and voids may exist which substantially weaken the material. In order to correct such defects, uncured resin material may be introduced into the cured composite structure to fill the delamination, crack, or void.
A typical apparatus for injecting resin into the composite structure is a syringe and needle, filled with uncured resin material. The needle of such an apparatus is inserted into the composite structure and pressure is applied to the syringe by hand or by a mechanical clamp to inject the resin into the structure. An alternative apparatus for injecting resin into cured composite parts is an injection gun in which air pressure forces resin from a tube through a needle and into the composite structure.
Both the syringe and the injection gun suffer from several deficiencies including the lack of an effective seal around the composite injection position which results in nonuniform pressure on the filling resin so as to cause uneven application of the resin within the delamination, crack, or void. An additional deficiency is the lack of effective control of the depth of the injection needle delivering the resin. By not controlling the depth of the resin injection, the delamination, crack, or void may not be located, and thus not filled, by the prior art injection equipment.
It would be desirable to develop an apparatus for injecting resin which was capable of introducing resin into a composite structure at a controlled depth. It would be further desirable for the apparatus for injecting resin to maintain an effective seal around the composite injection position in order to insure that a uniform pressure is exerted on the filling resin.